The present invention relates to exercise equipment and more particularly, to exercise equipment that uses a variable number of weights to resist exercise motion.
Exercise weight stacks are known in the art. Generally speaking, weight plates are arranged in a stack and movably mounted on at least one guide rod or rail. A selector rod is connected to a desired number of weight plates by a pin (or other suitable means known in the art). The selector rod and any selected weight plates are connected to a force receiving member by a cable (or other suitable means known in the art) which pulls the weight plates upward in response to exercise movement.
Although exercise weight stacks are prevalent in the exercise industry, they nonetheless suffer from certain shortcomings. For example, in order to provide a large amount of weight at a reasonable cost and within a reasonable amount of space, equipment manufacturers typically use a small number of relatively heavy weight plates. As a result, the amount of weight being lifted cannot be adjusted in small increments. On the other hand, a relatively large number of lighter weight plates may be used to provide smaller increments in weight adjustment, but the resulting equipment would be relatively more expensive and/or bulky.
Attempts have been made to address the issue of incremental weight adjustments. One such approach involves the provision of a loose half-weight (weighing one-half as much as a weight plate in the stack) that is selectively movable onto the top plate at the discretion of a user. This particular arrangement is not well suited for institutional environments because the half-weight may be lost or misused. Another prior art approach involves the provision of a half-weight or other fractional weight(s) that is/are selectively movable from a peg on the frame onto an aligned peg on the top plate of the stack. This approach not only fails to overcome the possibility of losing the half-weight, but it creates a balance problem during movement of the selected weights, and it also increases the potential for injury due to the proximity of the two pegs and their movement relative to one another. Yet another prior art approach involves the provision of a second, smaller weight stack comprising weight plates which weigh a fraction of the weight plates in the primary stack. Unfortunately, this approach adds significantly to both the cost and the size of the equipment.
Yet another prior art weight stack machine with supplemental or secondary weights is disclosed in French Patent No. 2,613,237 to Louvet. The Louvet machine includes a stack of primary weight plates movable along a guide rod in response to exercise movement, and a stack of secondary weights movable along the guide rod and selectively stored above the stack of primary weight plates. The secondary weights are supported by gates which are rotatably mounted on rigid frame members, and which have pegs that rotate into engagement with holes in the frame members. Each of the nine secondary weights has a mass equal to one-tenth the mass of one of the primary weight plates. One disadvantage of the Louvet machine is that nothing prevents a user from releasing a secondary weight without grasping the weight. As a result, the secondary weight may be free to drop downward onto the top plate in the primary weight stack, thereby increasing the likelihood of personal injury and/or damage to the machine. Also, each of the secondary weights is not separately supported by a respective gate. As a result, the entire stack of secondary weights may be released at one time, with or without a user holding onto any of the weights.
Still other prior art approaches are disclosed in Soviet Union Patent No. 1347-948-A and Japan Patent No. 10-118222. Each of these patents discloses first and second secondary weights which are movably mounted on discrete guide rods outside the planform of the primary weight stack. The secondary weights in the Soviet patent are pivotally mounted on respective, dedicated guide rods for movement into positions overlying the top plate in the primary weight stack. The secondary weights in the Japan patent are releasably secured to the top plate by a separate selector pin. A shortcoming common to both of these approaches is the need for separate guide rods for the secondary weights, and/or the imposition of non-aligned weight on the primary weight stack. In other words, despite all of the efforts discussed above, room for better solutions and/or improvements remains.
Generally speaking, the present invention relates to exercise methods and apparatus involving a stack of primary weight plates movably mounted relative to a frame, and multiple secondary weights selectively activated to provide relatively smaller increments of weight adjustment. The secondary weights include a first weight and a second weight which are supported by the machine frame in respective, vertically aligned and spaced apart positions, and which are selectively movable to respective active positions, acting on the top plate. Among other things, the first weight may be maneuvered between its inactive position and its active position without disturbing the second weight. On the other hand, the first weight and the second weight are also preferably configured to register with one another, so that they can be maneuvered together, if so desired.
The secondary weights may be configured to engage and disengage the frame in various ways, including rotation, translation, or a combination thereof. Also, the secondary weights may be configured with a central opening to accommodate passage of a cable interconnected between a force receiving member and the top plate in the primary weight stack. Moreover, the present invention may be implemented on new equipment and/or tailored for retrofit on existing equipment, and/or the present invention may be implemented so that the secondary weights act upon the top plate throughout an exercise motion or any desired portion thereof. Many of the features, variations, and advantages of the present invention will become apparent from the more detailed description that follows.